Packaging machines are known in which a continuous web of material is converted into a plurality of individual pouches. The continuous web of material is folded in half over a plow to form two continuous side panels joined by a bottom fold. The folded web is passed through a series of seal bars which seal the side panels together at predetermined locations to form a strip of pouches interconnected by transverse seals. A cutter cuts through each transverse seal to form individual pouches with unsealed top edges.
The individual pouches separated from the web are transferred to a pouch filling station. The top edges of the pouches are closed when transferred, with the side panels substantially flat. In the pouch filling station, the individual pouches are typically carried in clamps which reposition the pouches so that the top edges are open as they pass through a pouch filler. The pouch filler then fills the pouches with product as the top edges are held open. The clamps subsequently shift back to close the pouches downstream of the pouch filler. The pouches are then sealed and collected for transport.
The type of product being packaged often determines whether the packaging process should use a continuously or intermittently advancing web. Certain products, such as hard candy, require a fill based on weight instead of volume. Scale fillers require relatively long periods to fill a pouch. As a result, slower cycle continuous motion or intermittent motion is required to provide additional fill time. More free flowing products, such as sugar, may be dispensed using a diving funnel suitable for filling continuously advancing pouches. A machine capable of running both continuously and intermittently has not heretofore been known.
It is advantageous for a packaging machine to be capable of forming different sized pouches. For example, when packaging a particular product, it may be desirable to provide small and large pouches of the product. Accordingly, it is important that the packaging machine, including the pouch carrying apparatus, be adjustable for such different sized pouches.
Most conventional pouch carrying apparatus are incapable of adjustment, or require a significant amount of labor and down time to adjust for different pouch widths. Certain pouch carrying apparatus are only suitable for a single pouch size. Some of these machines, for example, have clamps directly attached to a single chain or chain set. To carry a different sized pouch, at least one clamp of each associated clamp pair must be removed and reattached at a different point along the chain. In the alternative, the entire chain set must be removed and replaced with a second chain set already having properly spaced clamps. As a result, adjusting such carrying apparatus for different sized pouches is overly difficult and time consuming.
Other pouch carrying apparatus, such as that disclosed in U.S. Pat. No. 4,956,964 to Jones, use a plurality of pouch-carrying frames interposed along a single chain or chain set. Each frame has a fixed first jaw and moveable second jaw, the jaws holding opposite sides of a pouch. The moveable second jaw is slideably mounted on rods so that the space between the first and second jaws may be adjusted, thereby adapting the frame to carry different sized pouches. As noted in Jones, however, the range of adjustment is limited by the frame size. For example, as stated at Col. 6, line 67 to Col. 7, line 4 of the '964 patent, a gripper unit having a 6-inch pitch (that is, a frame mounted on pin sets that are spaced six-inches apart) is suitable for handling pouches within a range of about 2.5 inches to 4.5 inches. For pouch sizes outside this range, the 6-inch pitch frames must be removed and replaced with different sized frames. Furthermore, to adjust each frame within the appropriate range, the moveable jaw of each frame must be individually repositioned. As a result, pouch width change overs are overly time consuming.
Furthermore, the machine disclosed in the '964 patent does not reliably indicate the position of both clamps. The machine can ascertain where the frame is and, therefore, where the fixed clamp is located. The machine can not, however, similarly determine where the movable clamp is because that clamp is positioned on the rods according to pouch size.
Pouch carrying apparatus must not only be capable of accepting different pouch sizes, but must also be capable of adjusting the relative distance between associated pairs of clamps to open and close the pouch for filling and sealing operations. As noted above, the severed pouches are typically transferred in a closed condition into the clamps of the pouch carrying apparatus. Before reaching the pouch filler, the spacing between each associated pair of clamps is reduced so that the side walls of each pouch bow outward to provide an open pouch. Each pouch is held in the open position as the pouch is filled. After filling, the relative distance between each clamp in an associated pair of clamps is increased back to approximately the original position to again provide a closed pouch. Each pouch is then carried through sealer rolls to seal the top end of the pouch.
It is overly difficult, however, to adjust the pouch opening and closing operations for different pouch widths. For example, the frame of the above-mentioned U.S. Pat. No. 4,956,964 to Jones supports a lever arm which is attached to the moveable jaw. As a result, the cams must be positioned properly along the path so that the moveable clamp is repositioned at the desired locations before and after the pouch filler. The cams must further have the appropriate profile so that the moveable clamp is repositioned the appropriate distance. The desired repositioning distance changes according to the pouch size. Accordingly, to run a different pouch size, each of the cams must be repositioned so that it is at the proper location and has the appropriate profile. As a result, it is overly burdensome and time consuming to adjust the pouch opening and closing operations.